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Finding the Fourth Proportional to 640.86, 884.28 and 420.18

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Solution

The fourth proportional to 640.86, 884.28 and 420.18 is: 579.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    640.86 : 884.28 = 420.18 : x
  2. Step 2: Convert to fraction form
    640.86/884.28 = 420.18/x
  3. Step 3: Cross multiply
    640.86x = 884.28 × 420.18
  4. Step 4: Simplify right side
    640.86x = 371,556.77
  5. Step 5: Solve for x
    x = 371,556.77/640.86
  6. Step 6: Final answer
    x = 579.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.